Inject current branch slug into the documentation link

Resolves #8995

GitCommands/Properties/AssemblyInfo.cs

@@ -3,5 +3,6 @@
 
 [assembly: AssemblyDescription("GitExtensions commands")]
 
+[assembly: InternalsVisibleTo("GitExtensions")]
 [assembly: InternalsVisibleTo("GitCommands.Tests")]
 [assembly: InternalsVisibleTo("GitUI.Tests")]

GitCommands/Settings/AppSettings.cs

@@ -8,6 +8,7 @@
 using System.Linq;
 using System.Reflection;
 using System.Text;
+using System.Text.RegularExpressions;
 using System.Windows.Forms;
 using GitCommands.Settings;
 using GitCommands.Utils;
@@ -62,6 +63,7 @@ public static class AppSettings
         public static readonly string UserPluginsDirectoryName = "UserPlugins";
         private static string _applicationExecutablePath = Application.ExecutablePath;
         private static readonly ISshPathLocator SshPathLocatorInstance = new SshPathLocator();
+        private static string? _documentationBaseUrl;
 
         public static Lazy<string?> ApplicationDataPath { get; private set; }
         public static readonly Lazy<string?> LocalApplicationDataPath;
@@ -117,6 +119,39 @@ static AppSettings()
             MigrateAvatarSettings();
         }
 
+        /// <summary>
+        /// Gets the base part of the documentation link for the current application version,
+        /// which looks something like "https://git-extensions-documentation.readthedocs.org/"
+        /// for the master branch, and "https://git-extensions-documentation.readthedocs.org/release-X.Y"
+        /// for a release/X.Y branch.
+        /// </summary>
+        public static string DocumentationBaseUrl
+        {
+            get => _documentationBaseUrl ?? throw new InvalidOperationException($"Call {nameof(SetDocumentationBaseUrl)} first to set the documentation base URL.");
+        }
+
+        internal static void SetDocumentationBaseUrl(string currentGitBranch)
+        {
+            if (_documentationBaseUrl is not null)
+            {
+                throw new InvalidOperationException("Documentation base URL can only be set once");
+            }
+
+            string? docVersion = null;
+
+            if (!string.IsNullOrWhiteSpace(currentGitBranch))
+            {
+                // We expect current branch to be something line "release/X.Y"
+                Match match = Regex.Match(currentGitBranch, "release/\\d*\\.\\d*");
+                if (match.Success)
+                {
+                    docVersion = $"en/{currentGitBranch.Replace("/", "-")}/";
+                }
+            }
+
+            _documentationBaseUrl = $"https://git-extensions-documentation.readthedocs.org/{docVersion}";
+        }
+
         public static bool? TelemetryEnabled
         {
             get => GetBool("TelemetryEnabled");
@@ -2058,5 +2093,7 @@ public override void SetValue<T>(string name, T value, Func<T, string?> encode)
         {
             AppSettings.SettingsContainer.SetValue(PathFor(name), value, encode);
         }
+
+        public void ResetDocumentationBaseUrl() => AppSettings._documentationBaseUrl = null;
     }
 }

GitExtensions/Program.cs

@@ -42,6 +42,8 @@ private static void Main()
             // There's no perf hit calling Initialise() multiple times.
             UserEnvironmentInformation.Initialise(ThisAssembly.Git.Sha, ThisAssembly.Git.IsDirty);
 
+            AppSettings.SetDocumentationBaseUrl(ThisAssembly.Git.Branch);
+
             ThemeModule.Load();
             Application.ApplicationExit += (s, e) => ThemeModule.Unload();
 

GitUI/CommandsDialogs/FormBrowse.cs

@@ -1881,7 +1881,7 @@ private void CloseToolStripMenuItemClick(object sender, EventArgs e)
         private void UserManualToolStripMenuItemClick(object sender, EventArgs e)
         {
             // Point to the default documentation, will work also if the old doc version is removed
-            OsShellUtil.OpenUrlInDefaultBrowser(@"https://git-extensions-documentation.readthedocs.org");
+            OsShellUtil.OpenUrlInDefaultBrowser(AppSettings.DocumentationBaseUrl);
         }
 
         private void CleanupToolStripMenuItemClick(object sender, EventArgs e)

GitUI/UserManual/StandardHtmlUserManual.cs

@@ -1,11 +1,10 @@
 using System;
+using GitCommands;
 
 namespace GitUI.UserManual
 {
     public class StandardHtmlUserManual : IProvideUserManual
     {
-        private const string _location = @"https://git-extensions-documentation.readthedocs.org/";
-
         private readonly string _subFolder;
         private readonly string _anchorName;
 
@@ -19,7 +18,7 @@ public string GetUrl()
         {
             var subFolder = string.IsNullOrEmpty(_subFolder) ? string.Empty : _subFolder + ".html";
 
-            return (_location + subFolder).Combine("#", _anchorName);
+            return (AppSettings.DocumentationBaseUrl + subFolder).Combine("#", _anchorName);
         }
     }
 }

UnitTests/GitCommands.Tests/Settings/AppSettingsTests.cs

@@ -3,6 +3,7 @@
 using System.IO;
 using System.Linq;
 using System.Reflection;
+using FluentAssertions;
 using GitCommands;
 using GitCommands.Settings;
 using GitCommands.Utils;
@@ -16,6 +17,27 @@ internal sealed class AppSettingsTests
     {
         private const string SettingsFileContent = @"<?xml version=""1.0"" encoding=""utf-8""?><dictionary />";
 
+        [TestCase(null, "https://git-extensions-documentation.readthedocs.org/")]
+        [TestCase("", "https://git-extensions-documentation.readthedocs.org/")]
+        [TestCase("\t", "https://git-extensions-documentation.readthedocs.org/")]
+        [TestCase("master", "https://git-extensions-documentation.readthedocs.org/")]
+        [TestCase("feature/test/mystuff", "https://git-extensions-documentation.readthedocs.org/")]
+        [TestCase("releases", "https://git-extensions-documentation.readthedocs.org/")]
+        [TestCase("releases/4.5", "https://git-extensions-documentation.readthedocs.org/")]
+        [TestCase("release", "https://git-extensions-documentation.readthedocs.org/")]
+        [TestCase("release/a", "https://git-extensions-documentation.readthedocs.org/")]
+        [TestCase("release/5", "https://git-extensions-documentation.readthedocs.org/")]
+        [TestCase("release/a4.5", "https://git-extensions-documentation.readthedocs.org/")]
+        [TestCase("release/4.5", "https://git-extensions-documentation.readthedocs.org/en/release-4.5/")]
+        [TestCase("release/40.501", "https://git-extensions-documentation.readthedocs.org/en/release-40.501/")]
+        public void SetDocumentationBaseUrl_should_currectly_append_verison(string currentGitBranch, string expected)
+        {
+            AppSettings.GetTestAccessor().ResetDocumentationBaseUrl();
+
+            AppSettings.SetDocumentationBaseUrl(currentGitBranch);
+            AppSettings.DocumentationBaseUrl.Should().Be(expected);
+        }
+
         [Test]
         [TestCaseSource(nameof(TestCases))]
         public void Should_return_default_value(PropertyInfo property, object value, object defaultValue, bool isSetting)

UnitTests/GitUI.Tests/UserManual/StandardHtmlUserManualFixture.cs

@@ -1,4 +1,5 @@
 using FluentAssertions;
+using GitCommands;
 using GitUI.UserManual;
 using NUnit.Framework;
 
@@ -12,6 +13,9 @@ public class StandardHtmlUserManualFixture
         [TestCase("merge_conflicts", "merge-conflicts", "https://git-extensions-documentation.readthedocs.org/merge_conflicts.html#merge-conflicts")]
         public void GetUrl(string subFolder, string anchor, string expected)
         {
+            AppSettings.GetTestAccessor().ResetDocumentationBaseUrl();
+            AppSettings.SetDocumentationBaseUrl("master");
+
             var sut = new StandardHtmlUserManual(subFolder, anchor);
 
             sut.GetUrl().Should().Be(expected);